Partial Association - Assignment #9


1. Consider the following crossclassification table between sex and political affiliation. What is the appropriate measure of association for this zero order table. Calculate that measure. Now consider a third variable, age, and review its relation in the first order partial tables. Calculate the measure of association for these first order partials and tell us, within the context of the statistical elaboration model, what is going on with this control variable.

The Marginal (Zero-Order) Table

All

Male

Female

Total

Rep

30

10

40

Dem

10

30

40

Total

40

40

80

The Partial Tables

Young

Male

Female

Total

Rep

10

10

20

Dem

10

10

20

Total

20

20

40

Old

Male

Female

Total

Rep

20

0

20

Dem

0

20

20

Total

20

20

40

2. From Government statistcis, you compute a correlation of .55 between unemployments rates (X) and suicide rates (Y). A fellow student suggests the reason may be related to a reduction in income (Z) among unemployed. If the correlation between unemplyment rates (X) and income (Z) is 0.60 and the correlation between suicide rates (Y) and income (Z) is 0.40, what could you say about this student's suggestion (Remember what to do after you calculate the partial correlation coefficient).